1. Field of the Invention
The present invention relates to a semiconductor device and an electronic unit.
2. Description of the Related Art
A semiconductor device having a plurality of semiconductor elements arranged one on top of another has conventionally been proposed. For instance, the semiconductor device disclosed in JP-A-2004-119684 includes a first semiconductor element mounted on a substrate, and a second semiconductor element mounted on the first semiconductor element. The second semiconductor element is smaller in dimensions than the first semiconductor element. Each of the first semiconductor element and the second semiconductor element has a principal surface on which a plurality of electrodes are formed. Each of the electrodes of the second semiconductor element is electrically connected to the substrate or one of the electrodes of the first semiconductor element via a wire.
The above-described conventional semiconductor device allows only a relatively low current to flow, because usable wires are limited in terms of their materials or thicknesses. Moreover, in the conventional structure, the arrangement of the wires may become complicated when the first semiconductor element and the second semiconductor element are electrically connected to each other by wires. Further, the principal surface of the first semiconductor element and the principal surface of the second semiconductor element are spaced apart from each other only by a distance approximately corresponding to the thickness of the second semiconductor element. This causes the function of the first semiconductor element and the function of the second semiconductor element to interfere with each other, which may hinder the function of each element from being properly exerted.